Something tasteless or intellectually inferior that is devoid of any intelligence - usually in pop culture. Lacking in refinement and good taste. Often but not always appealing to the absolute lowest common denominator.
"Sorry, Charlie - the second the silly sound effects and music with the low-brow humor start, I'm out the door. No primetime TV for me!"
Mr 1: "Went out with Sarah last night"
Mr 2: "Dude she's low-brow"